[*] 107. Two sigmas brought together by inflection become ς: βέλεσι for βέλεσ-σι missiles, ἔπεσι for ἔπεσ-σι words (98), τελέσαι for τελέσ-σαι (from τελέω accomplish, stem τελεσ-).

a. σς when = ττ (78) never becomes ς.

http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0007:smythp=107

#AncientGreek